'Costumer' definitions:

Definition of 'costumer'

From: WordNet
noun
Someone who designs or supplies costumes (as for a play or masquerade) [syn: costumier, costumer, costume designer]

Definition of 'Costumer'

From: GCIDE
  • Costumer \Cos"tum`er\ (-t?m`?r), n. One who makes or deals in costumes, as for theaters, fancy balls, etc. [1913 Webster]